Nelson Creek Fish Passage Restoration Project

Nelson Creek is a tributary to the upper Yakima River at river mile 193 about 5 miles west of Cle Elum, Washington. A perched, undersized culvert (24" plastic pipe) at the confluence Nelson Creek and the Yakima River created a fish passage barrier into important tributary rearing habitat in Nelson Creek.

KCT addressed this problem by removing the old perched culvert and installing an 11-foot span horizontal ellipse-shaped culvert, with an 8-foot rise, to support a forest road. The new culvert is partly filled with cobbles, gravel and sand to form a semi-natural stream channel connecting the Yakima River with upstream habitat in Nelson Creek. The larger drainage structure substantially improves flood flow, passage of wood and debris, and natural sediment transport. Upstream of this new culvert and its semi-natural streambed is a constructed 20-foot long roughened channel to minimize head cut into the natural Nelson Creek streambed.